Blog post: The importance of proteins, and good plant based sources

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Why we need protein[i]

Protein is essential for the growth and maintenance of all body tissues, including muscles, bone, skin and blood. Protein is also needed for the production of hormones and enzymes, for the immune system, and to maintain important balances in the body including fluid and pH balance.

In an average weight person, protein makes up about 20% of body mass. Whilst everyone needs protein, its role in growth and repair makes it especially important for growing children, during pregnancy, those who exercise a lot and those recovering from an injury.

Dietary Sources of Protein

Protein is made up of amino acids. The body commonly uses about 20 amino acids, and nine of these are essential; this means that the body cannot make them, so you need to get them in the diet. [ii]

When we talk about food sources of protein, we generally divide them into complete and complementary sources. Complete proteins contain all of those nine essential amino acids, roughly in the proportion that the body needs them, whilst complementary proteins don’t contain them all, or are lower in some. [iii]

Animal proteins (that includes meat, poultry, fish, dairy and eggs) are complete proteins, while most plant sources are complementary. This doesn’t make them ‘worse’ sources, it is just important that you get a variety if you don’t eat animal proteins, to ensure you get all of the different amino acids.

Sources and approximate grams of protein per portion iii
Animal Sources Plant Based Sources
Meat (30g/100g) Quinoa (a complete protein) (14g/100g)
Poultry (30g/100g) Pulses: Lentils, chickpeas, beans and peas (8g/100g)
Fish (20-25g/100g) Tofu (8g/100g)
Eggs (12g/2 large eggs) Nuts and seeds (8-10g/50g)
Dairy: cheddar cheese (12g/ 50g) Oats (11g/100g)
Dairy: milk/ yogurt (3-5g/100g) Rice, other grains and many vegetables all also contain a certain amount of protein but don’t rely on them as your only source

 How much protein do you need?

The UK guideline is 0.75g of protein for every kg of body weight[iv]. I.e. someone weighing 60kg would need 50g of protein from the diet each day. The EU guidelines are slightly higher at 0.83g/kg[v]. Guidance is also higher for children and pregnant or breastfeeding women.

These guides are a minimum amount that is considered necessary to avoid risks associated with a protein deficiency. The average Western diet in fact includes a significantly higher amount of protein. Whilst there are risks associated with having too much protein, the World Health Organisation advises that twice the guideline amount is likely to be without risk.[vi]

Many of the issues associated with excess protein intake are specific to the consumption of animal protein. This is because these products are generally also fairly high in saturated fat, so may encourage weight gain. A high protein intake can also increase the work of the kidneys, because they are instrumental in the breakdown of protein. An excess intake may therefore increase the risk of kidney disease[vii]. Research has also shown links between high animal protein intake and increased risk of heart disease,[viii] as well as links to certain cancers[ix]

Protein rich meal and snack ideas

Meals:

Plant based protein snacks:

  • Nut butter on oatcakes or apple slices
  • Hummus, or dips made from beans (butter beans make a lovely creamy dip)
  • Oaty flapjacks (make your own so you can avoid too much sugar which many bought bars are laden with)
  • Handful of unsalted mixed nuts and seeds
  • Crispy chickpeas – bake them in the oven with some spices for an irresistible snack!
  • Falafel (also great as a meal in wholemeal wraps with lots of crunchy salad)

References:
[i] Haas, E. (2006) Staying Healthy with Nutrition. USA: Crown Publishing Group pp.162-166
[ii] Osiecki, H. (2014) The Nutrient Bible (9th Edition). Australia: AG Publishing
[iii] British Nutrition Foundation (2018). Protein. Available at https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/protein.html
[iv] British Nutrition Foundation (2017) Nutrition Requirements. Available at
https://www.nutrition.org.uk/nutritionscience/nutrients-food-and-ingredients/nutrient-requirements.html
[v] EFSA (2017) Dietary Reference Values for nutrients Summary report. Available at
https://www.efsa.europa.eu/sites/default/files/2017_09_DRVs_summary_report.pdf and
[vi] WHO/FAO/UNU Joint report (2002). Protein and Amino Acid Requirements in Human Nutrition. Available at
http://apps.who.int/iris/bitstream/10665/43411/1/WHO_TRS_935_eng.pdf 
[vii] Schwingshackl, L. and Hoffmann, G. (2014) “Comparison of High vs. Normal/Low Protein Diets on Renal Function in Subjects without Chronic Kidney Disease: A Systematic Review and Meta-Analysis” in PLOS One 22;9(5). Available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4031217/
[viii] Clifton, P. (2011) “Protein and Coronary Heart Disease: The Role of Different Protein Sources” in Current Atherosclerosis Reports 13.6 pp.493-498 Available at https://www.ncbi.nlm.nih.gov/pubmed/21912836
[ix] World Cancer Research Fund (2007) Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective. Available at https://www.wcrf.org/sites/default/files/Second-Expert-Report.pdf

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